import java.util.Stack;

public class Test {
    public static void main(String[] args) {
        Stack<Integer> stack=new Stack<>();
        //push入栈
        stack.push(12);
        stack.push(23);
        stack.push(34);
        stack.push(45);
        stack.push(56 );

        //pop出栈
        Integer x= stack.pop();

        System.out.println(x);

        Integer y=stack.peek();
        System.out.println(y);

        boolean flg=stack.isEmpty();
        System.out.println(flg);


        MyStack myStack=new MyStack();
        myStack.push(1);
        myStack.push(2);
        myStack.push(3);
        System.out.println(myStack.pop());
    }
}
